Malcolm



. UNITED STATES PATENT OFFICE.

MALCOLM MACLEOD, or MANCHESTER, COUNTY OF LANCASTER, ENGLAND.

FS'FHALT PAVEM EN'T.v

SPECIPICATIOR forming part of Letters Patent No. 361,953 dated April 26,1887. Application filed September-'3, 1886. Serial-No. 212,625. (Nospecimens.) Patented in England anuiiry 12, 1885, 30.406.

To all whom, it may concern} Be it known that I, MALCOLM .MACLEOD, a

subject of the Queuof Great Britain, and a, fesident of 66 Deansgate,Manchester, in the countyof LancastenEngland, have invented anImprovement in Asphalt Pavements, (Eng-' lishLetters Patent for whichwere issued to I me January 12, 1885, No. 406;) and I do hereby I fromthe following specification and claims.

declare the following to be a full ,clear, and exact description of thesame.

Thenature of my invention will fully appear I am-enabled by my device tolay a bed of asphalt of a low melting temperature beneath a bedor'surface of higher melting temperatu re, the intermediate layer oflimestone, granite, grave], or other similarmateriai prevent- 7 ing thehigh temperature of the upper and harder asphalt from melting, andsomixing itself with the lower or softer asphalt.

I have several methods of carrying out my invention, but prefer thefollowingas the best: I vprepare a sufficient quantity of, say, Britishasphalt, composed of pitch and oil, in the usual way. This varnish, whensulficient-ly prepared, I pour over broken limest'one, (by preference,but can ,use any hard material.)

Thisi I spread'over the surface it is intended to cover with asphalt,and compress it by roll- 3- ing or ramming. Over this surface I spread alayer of limestone, granite, gravel, or other suitable material ofabout, say, an inch in diameter. This'I ram into the rolled surface andpass over all a heavy roller 'until thei limestone, granite, gravel, orother suitable material is forced into thefoundation to about half itsthickness, and the whole is thoroughly compressed. I then remo've anyloose limestone or other material. Upon the foundation thus prepared Ilay a bed or surface of rock or other hard-asphalt prepared in theusual.

way. The layer of limestone or other mate:

rial nowprevents the floating oils or other substances of the .softerorlower asphalt fromrising into the rock or other hard asphalt, andabsorbs them partly into itself. The hot rock or other hard asphaltreadily adheres to the limestone, granite, orjother intermediate materiahyand the whole forms a homogeneous mass, the intermediate layer oflimestone or described.

other suitable material acting as a key to connect thetwo asphalts.

In the case of roadways, where a safer hold forhorses isdesired, I laythe foundation in .the way described for pavements, but prefer toput'down the hard asphalt in two layers, viz: After the basic layer oflimestone or other material is. laid I'cover'it with a layer of hot rockasphalt, and upon it spreadevenly'pie'ces of stone or other similarmaterialand compress theminto the hard asphalt while it is hotfso thattheiruppersurfaces are level with the completed heightof the roadway. 'Ithen fill in the spaces between the stones with hot gravel-stones,broken stone of all kinds, and,

generally, all hard refuse material.

What I claim as new is 1. Apavement, roofing, or flooring composed oftwo layers of asphalt, said layers being of different meltingtemperatures, and

unitedto one another without mixing by means of anintermediate keying oflimestone, ranite, or other suitable material projecting mm the lowerthrough the upper layer, of asphalt,-substantiallyas described.

2. A composite pavement consisting of a lower layer of asphaltum orcement, a superincumbent layer of asphaltum or cement, and .anintermediate layer of stony particles "projecting into the lower layeror stratum "andthrough the upper stratum of asphaltum or cement,substantially as and for the purposes MALCOLM MAOLEOD.

Witnessesr ARTHUR O. HALL, ALBERT E. HALL,

9 Maruth, Manchester, England.

